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(CNN)Residents of northern and central parts of California, already drenched by weeks of rain, prepared for possible flooding and landslides as another round of storms pummeled the state.

More than 14 million people are under a flood warning or flash-flood watch and residents have been advised to prepare for evacuations. Six to 10 inches of rain could fall from San Francisco eastward before the storm tapers off, CNN meteorologist Dave Hennen said Monday.

"Gather important items, documents and medications in a 'go bag' in case you need to evacuate quickly," the National Weather Service in Sacramento said in an advisory. " Don't forget to plan for your pets, too. Make sure your vehicles have a full tank of gas."

In Salinas, south of San Francisco, some evacuating residents had to be rescued by boat Monday, CNN affiliate KSBW reported. Other people in Monterey County have been waiting days for electricity to be restored.

San Jose resident Ruben Lechuga told CNN affiliate KGO he hoped his local creek wouldn't spill, adding, "But if it does, we just move out for a while and see what happens. It's all we can do."

Photos:Severe storms pound California

Rescue crews steer a boat full of residents in a flooded San Jose, California, neighborhood on Tuesday, February 21. One of Southern California's most powerful storms in recent years has caused flooding, power outages and blackouts across the region.

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Photos:Severe storms pound California

Part of the shoulder and one lane of westbound Highway 50 gave way on February 21, near Pollock Pines after heavy rains in the area.

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Photos:Severe storms pound California

Signs block a road in Morgan Hill, which runs into the overflowing Coyote Creek, on February 21.

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Photos:Severe storms pound California

Residents walk down a flooded road in Salinas, California, on Monday, February 20.

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Photos:Severe storms pound California

People stop to watch water flow into the iconic Glory Hole spillway at the Monticello Dam on February 20, in Lake Berryessa. This is the first time in over a decade that water has been high enough to flow into the 72-foot diameter spillway.

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Photos:Severe storms pound California

A member of Cal Fire, right, talks to workers on the Oroville Dam project in front of the main spillway in Oroville on February 20. Officials are keeping an eye on the dam after mandatory evacuations last week amid concerns an emergency spillway could fail and threaten communities.

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Photos:Severe storms pound California

Floodwaters cross over Interstate 5 at Williams, backing up traffic in both north and southbound lanes for hours on Saturday, February 18.

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Photos:Severe storms pound California

Tina Dry mops up water and mud that seeped into her family's diner, Kim's Country Cafe, after area storms brought flood-level water to the Colusa County town of Maxwell on February 18.

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Photos:Severe storms pound California

Barr Torrens plays in flooded neighborhood streets after a deluge of rain and runoff flooded much of Maxwell on February 18.

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A woman with her dog stops to look at a tree that crushed a car Saturday, February 18, in the Sherman Oaks section of Los Angeles.

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Inspectors check out a sinkhole that formed in Los Angeles' Studio City neighborhood on February 18 after the severe storm hit.

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Photos:Severe storms pound California

A Los Angeles apartment building is damaged after a 75-foot-tall tree crashed into it on Friday, February 17.

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Photos:Severe storms pound California

A firefighter carries a woman after floodwaters engulfed her car on a street in Los Angeles' Sun Valley neighborhood on February 17.

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A bicyclist tries to maneuver through a flooded street in the Sun Valley area on February 17.

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Large waves pound the shore at El Porto in Manhattan Beach as storms slam the Los Angeles area on February 17.

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A man attempts to board a bus on a flooded street near the Sun Valley area of Los Angeles on February 17.

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The downpour doesn't deter a pedestrian in Los Angeles on February 17.

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Pacific Coast Highway is reduced to one lane at the California Incline after mud and other debris washed down from bluffs in Santa Monica on February 17.

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The strong Pacific storm also is expected to bring howling winds and mountain snow to central and northern parts of California, the National Weather Service reported.

Meteorologists explain the current weather patterns by saying that as a condensed column of moisture moves inland, the water vapor sweeps over the mountains, cools and forms an "atmospheric river," bringing heavy precipitation.

Strong southerly winds with gusts of 45 to 65 mph are expected to whip through the Central Valley and surrounding foothills.

The National Weather Service said the storms carry a threat of rock and mudslides, potentially making travel dangerous.

DownTown San Francisco surpassed their entire water year (Oct-Sep) precip normal (23.65in) this AM. At 10AM the total was 24.50in.#CAwx

In Orinda, east of Berkeley, PG&E crews worked over the weekend to shore up a transmission tower threatened by a possible landslide, KGO reported. The tower is so remote, crews used a helicopter to transport some of their equipment.

Roads already closed or partially blocked by mudslides on Monday included northbound State Road 1 in Santa Cruz County and Sir Francis Drake Boulevard in Martin County, authorities said on social media.

Deadly downpour

Northern California already is soaked from heavy rains that have pummeled the state since early January. More stress on levees, dams, rivers, creeks and streams is expected.

Officials are also keeping an eye on the Oroville Dam, after there were mandatory evacuations last week amid concerns an emergency spillway could fail and threaten communities. Authorities said Monday the water level in the lake is now 849 feet, the flood control stage normally maintained this time of year.

"Additional heavy rain will only make matters worse," CNN meteorologist Derek Van Dam said. "There could be flooding in places that haven't flooded in many years. The time to take action is now."

The Glory Hole spillway in Lake Berryessa spilled over for 1st time in 10 yrs. This morning we went to see the 72' diameter spillway funnel. pic.twitter.com/xDb2QEQnaH

The storms, along with intense wind shears, produced four tornadoes in the San Antonio area, the agency said on Twitter. Two were rated EF-1 with 105 and 110 mph winds, and the other were EF-0 with 70 and 85 mph winds.

At least 100 homes were reported damaged late Sunday in San Antonio, the National Weather Service told CNN. Officials were sending out teams to survey losses.

Nearly 12,000 customers in the San Antonio area remain without power, CPS Energy said. Two minor injuries were reported, officials said.